First report of microplastics in water and sediments of the alkaline Bagno dell’Acqua Lake (Pantelleria Island, southern Italy)

Abstract

Microplastics are ubiquitous in aquatic ecosystems and lakes are considered important sinks for this contaminant. In this study, we assessed for the first time the occurrence and spatial distribution of microplastics in surficial waters and sediment of a small alkaline lake located in the National Park of Pantelleria Island (Central Mediterranean Sea). The island is small, scarcely populated, not industrialized and ∼70 km far from the southern European and northern African shores. Water samples were collected in triplicates in different sectors of the lake using a 10 L metal bucket, while sediment sampling was carried out at seven stations along the lake shoreline, plus one station at 3.6 m depth. Results show a homogeneous distribution of microplastic in surface waters, dominated by fibers (∼90%), with a mean concentration of 0.13 ± 0.04 MP/L, which is lower than most of the lakes worldwide. Conversely, microplastics in sediment had a higher proportion of fragments and films (50%) and their concentrations range from 0 to 540 MP/kg. The highest abundance was recorded in the western sector, where most of touristic activities concentrate, and at the 3.6 m depth station, thus suggesting that the deeper parts of the lake may retain the majority of microplastics entering the system. This study shows that even in small lakes far from major anthropic pressures, sediment may contain microplastics in striking abundances, pointing out the need to assess rural and remote lakes, at present much understudied compared to lakes in highly populated regions.